WiFi and DAS Need Wires to Function

It may seem strange that WiFi and DAS need wires to function and many may wonder why a wireless system even requires a cabling infrastructure. Today, most people presume they will receive uninterrupted excellent wireless connectivity  like WIFI and DAS (Distributed Antenna System), but they don’t realize that all “wireless” systems employed in a commercial development will require a cabling infrastructure. In other words: Wireless needs wires. 

Wireless Technology Evolution 

All technology systems evolve at a fast pace as compared to most other products and services we use. And wireless technologies have been evolving quickly for decades even compared to other technology systems. Wireless Industry experts have predicted that by 2025:

Wireless Communications - Then and Now

WWII was the first war in which troops employed wireless communications, and after the war in 1945, the U.S. Citizens Band Radio Service  provided radio band access for personal communication.  Most of us are likely familiar with  radio use of the citizen’s band known as Ham radio (amatuer users), and those of us of a certain age probably remember someone whose hobbies included a “CB radio”.  But in addition to Ham radio operators, it was farmers,  governmental agencies, and U.S. companies who embraced and implemented solutions using defined MHz bandwidths for wireless communication after the war.

A DAS is an interconnected series of antennas spatially separated to provide cellular/wireless service over a geographic area.  The geographic area varies from a few antennas serving a small town, or a series of antennas to provide coverage over hundreds or even thousands of miles. The vast cabling  infrastructure required to deliver that much signal across that many miles was and is provided by a select few companies such as AT&T, Verizon and others.Use in specific locations (buildings and campuses) became a reality when  A. A. M. Saleh, A. J. Rustako and R. S. Roman presented the idea for Distributed Antennas for Indoor Radio Communications in 1987.  

As we entered the 21st century,  large  venues were using a DAS.  The DAS antenna was  most often located on the roof of a building.  At that time, it was costly to implement a DAS so only large venues could justify the expense of implementing.   The progressive changes in the decades that followed gave rise to less pricey systems that can serve much smaller spaces.

Today, the wireless systems that are commonly used in commercial buildings include:

• Commercial Distributed Antennae System (DAS) For commercial developments, a DAS strengthens the native signal (provided by AT&T, Verizon and others) either within a building or across a campus.   This becomes necessary when the number of people who will use the building or campus are expected to require more signal than the native signal provides.  Relevant to the need for a DAS is that some of the building materials used will weaken or block the existing signal.   The  DAS is often needed to provide adequate signal inside the building or throughout the campus.   If there is a DAS implemented, it will rely on a cabling infrastructure to enhance the signal in the building.  These systems require testing of the native signal after construction has completed erecting the walls.  The final design is documented after that.

• DAS/ERRS (First Responders System) These systems enhance radio communication for first responder personnel.  It is an antenna based system like its commercial DAS cousin mentioned above. The largest difference is that a DAS/ERRS must operate when the building is in distress (fire for example)  It operates on a protected licensed frequency to assure that it remains active for first responders during an emergency.  Understandably,  it is most often a separate DAS system, and unlike the DAS intended for the rest of the population, the DAS/ERRS  may be required by state or local code in many metropolitan areas.  There is a structured cabling infrastructure required to insure adequate coverage for first responders in the building, just as it is for the commercial DAS.  
• WiFi Systems -  Unlike a commercial DAS and a DAS/ERRS,  WiFi systems are not relying on the native radio signal.  They provide localized wireless access for  technology devices such as personal computers, laptops, tablets and IoT devices within a building or the surrounding campus.  The system will usually consist of a controller/head-end, data switches, Wireless Access Points (WAPs) and the cables in between.  However, like the DAS and DAS/ERRS, WiFi requires a structured cabling infrastructure.  The WiFI solution varies in size based on the physical size, and the design of the building(s).

The Cabling Infrastructure for a DAS, DAS/ERRS or WiFi 

A commercial DAS and a DAS/ERRS system will each need to test for the native signal to determine the  final design and required system to install. The test for native signal should happen during construction after walls are up. Once the test is complete, a final design can be documented. A technology consultant who is on the architect’s design team can provide initial risers to account for the places and spaces that the DAS or DAS/ERRS will require. If it is already known to be required, the technology consultant can provide suggestions for someone to provide the coverage heatmap and a final design.  And the technology consultant’s preliminary design efforts help avoid issues such as available space in the MDF room or available conduit to a unique location after the walls are up.

The WiFi system can also have a preliminary design before construction begins.  The design will address the  pathways and spaces for the WiFi hub (the collective equipment that creates and distributes signal).  The individual devices (wireless access nodes)  to which your PC, laptop or tablet connects can be designed to placeholder locations.  During construction, after the heatmap determines signal requirements, a few of the wireless nodes may move by a few feet.  Perhaps one or two  wireless nodes may be added. A good technology provider can design the pathways, spaces and general requirements during design, before construction completes the walls, and the heatmap is provided. 

When technology systems are discussed, the cabling infrastructure is the backbone for each of the systems (low voltage in this case).  In a discussion of wireless systems, the cabling infrastructure may be overlooked during design, unless there is a technology consultant on the design team. As it is with every other technology system, getting the wireless infrastructure designed correctly the first time will save an owner money by avoiding errors and delays associated with a flawed design which is seen only after construction has completed erecting the walls.

NTI’s design team is led by our principals and/or subject matter specialists to address each project’s unique vision.  They lead our designers and drafting professionals assigned to each project. As students of the industry, each principal, specialist and designer can be both teacher and student insofar as we help educate each other with the objective of providing a best in class design each and every time.

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